Here Comes the Sun!

According to a recent Solar Activity Update by the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center, “Solar activity picked up at the end of November into early December, 2020, as several sunspot groups emerged or rotated onto the visible disk”.  The update continues: “Solar activity is anticipated to slowly increase over the upcoming years towards the predicted solar maximum peak around July, 2025.” This is great news for observers of our nearest star! At times this year, there had been month-long sunspot “droughts” with no or few sunspots on the solar disk.

The return of Sun as a target of interest has led to a sudden uptick in Solar image postings to social media these past few weeks. 

The lead-off image at the top of this blog was made by Antonio Agnesi in Italy. It was such a good image, we were surprised to learn it was his first attempt at solar imaging!  It was made with our compact 70mm Tele Vue Ranger telescope (now superseded by the Tele Vue-60 APO). Antonio tells us:

The Ranger was my first serious telescope: I bought it maybe 23-years ago, and it still is my favorite “grab and go”scope for quick observing, solar imaging included.

It’s always nice to hear how our older scopes are still being used and cherished by their owners as the decades go by. 

Mauri Rosenthal captured the fantastic sunspot images above and “maelstrom” around Sunspot 2781 below with a  setup that consists of a Questar 3.5″ Maksutov capped with a Baader D-ERF (Energy Rejection Filter) in the front and  DayStar Quark Hydrogen-alpha set up in the back. He achieves the desired effective focal length using a Tele Vue 2.5x Powermate and 0.5x focal reducer. The camera is a QHY 5III 174M mono camera. He images just north of New York City and told us the following about his 2x and 2.5x Tele Vue Powermates:

I think it’s widely recognized that Powermates enable Quarks to perform well in a range of scope configurations. I’m very pleased with the 1.25″ 2.5x model for streamlined setups where weight is a consideration; and when the scope and mount can handle it, the 2″ 2x is very nice indeed.

The “Sunspot Number”

You might see something called the “Sunspot” number on websites like Spaceweather.com. While they often do not correspond to the number of sunspots visible in your amateur telescope, they do convey information useful to professional solar astronomers.

 

The number is derived by first collecting sunspot group and individual sunspot counts from various solar observation stations.  The group count is multiplied by 10 and added to the individual count. Therefore, on days when a station sees no visible sunspot, their  “Sunspot Number” is zero. On days where the count shows a single sunspot, the group count is one and the “Sunspot Number” is 11. Because resolution and observing conditions vary with each station, a scaling factor modifies the results at each location before combining them into the official “Number”.

 

Spaceweather.com suggests that amateur astronomers can estimate the number of sunspots visible in a small scope by dividing the daily “Sunspot Number” by 15.

 

One of the official sources of these counts is the Solar Influence Data Analysis Center, part of the Royal Observatory of Belgium. They say their observation stations are located in over 30 different countries and only 30% of these are at professional observatories.  The rest are amateur observers — a perfect fit for many of our blog readers wishing to participate in a pro-am astronomy project. For information on how you can contribute to the Sunspot Number, see their website for details.